Do you know what's in the carb now for jetting?
Find someone, anyone that has jets both 2 and 4 sizes smaller than what's in there now. Any old holley carbs laying around you can swipe jets from.
Closed chambered especially quench stuff usually doesn't like more than 34* of total timing.
Between timing and jetting alone, it could be off 50hp... DAMHIK!!!
Had an engine that was 1 point rich on jetting, 35 hp gain at peak when it was right. 4 degrees off in timing 15 hp. That alone is worth a LOT of real estate covered at the track.
You'll get it sorted out.